#pragma once
#include<iostream>
#include<unordered_map>
#include<vector>
#include<thread>
#include<time.h>
#include<assert.h>
#include<Windows.h>
#include<algorithm>
#include<map>
#include<mutex>
#include<thread>
using std::cout;
using std::endl;

#ifdef _WIN32
  #include<Windows.h>
#else
  //...
#endif

static const size_t MAX_BYTES = 256 * 1024;
static const size_t NFREELIST = 208;
static const size_t NPAGES = 129;
static const size_t PAGE_SHIFT = 13;

#ifdef _WIN64
  typedef unsigned long long PAGE_ID;
#elif _WIN32
  typedef size_t PAGE_ID;
#else
//linux
#endif

//直接去堆上按页申请空间
inline static void* SystemAlloc(size_t kpage)//相当于直接把函数调用的地方换成函数，节省调用时间；
{
#ifdef _WIN32
	void* ptr = VirtualAlloc(0, kpage << 13, MEM_COMMIT | MEM_RESERVE, PAGE_READWRITE);
#else
	//linux下brk  mmap等
#endif
	if (ptr == nullptr)
		throw std::bad_alloc();

	return ptr;
}

inline static void SystemFree(void* ptr)
{
#ifdef _WIN32
	VirtualFree(ptr, 0, MEM_RELEASE);
#else
	//sbrk unmmap等
#endif
}


static void* &NextObj(void* obj)//加&
{
	return *(void**)obj;//32位下为4字节，64位下为8字节
}

//管理切分好的小对象的自由链表
class FreeList
{
public:
	void Push(void* obj)
	{
		assert(obj);//assert是一个宏，对一个条件表达式进行判断，若为真，则继续运行，这里保证obj不为空，也就是得有obj。
		//头插
		//*(void**)obj = _freeList;
		NextObj(obj) = _freeList;
		_freeList = obj;

		++_size;
	}
	void PushRange(void* start, void* end,size_t n)
	{
		NextObj(end) = _freeList;
		_freeList = start;

		_size += n;
	}

	void PopRange(void* start, void* end, size_t n)
	{
		assert(n >= _size);
		start = _freeList;
		end = start;
		for (size_t i = 0; i < n - 1; i++)
		{
			end = NextObj(end);
		}
		_freeList = NextObj(end);
		NextObj(end) = nullptr;
		_size -= n;
	}
	void* Pop()
	{
		assert(_freeList);
		//头删

		void* obj = _freeList;
		_freeList = NextObj(obj);
		--_size;

		return obj;
	}
	bool Empty()
	{
		return _freeList == nullptr;
	}
	size_t& MaxSize()
	{
		return _maxSize;
	}

	size_t Size()
	{
		return _size;
	}
private:
	void* _freeList=nullptr;
	size_t _maxSize = 1;
	size_t _size=0;
};

class SizeClass
{
public:

	static inline size_t _RoundUp(size_t bytes, size_t alignNum)
	{
		return (((bytes)+alignNum - 1) & ~(alignNum - 1));//位运算
	}
	static inline size_t RoundUp(size_t size)//inline:适合用于频繁调用的小函数
	{
		
		if (size <= 128)
		{
			return _RoundUp(size, 8);
		}
		else if (size <= 1024)
		{
			return _RoundUp(size, 16);
		}
		else if (size <= 8*1024)
		{
			return _RoundUp(size, 128);
		}
		else if (size <= 64 * 1024)
		{
			return _RoundUp(size, 1024);
		}
		else if (size <= 256 * 1024)
		{
			return _RoundUp(size, 8*1024);
		}
		else
		{
			return _RoundUp(size, 1 << PAGE_SHIFT);
		}
	}
	//一次threadcache从中心缓存获取多少个
	static size_t NumMoveSize(size_t size)
	{
		assert(size > 0);
		if (size == 0)
		{
			return 0;
		}
		int num = MAX_BYTES / size;
		if (num < 2)
			num = 2;
		if (num > 512)
		{
			num = 512;
		}
		return num;
	}

	//计算一次向系统获取几个页

	static size_t NumMovePage(size_t size)
	{
		size_t num = NumMoveSize(size);
		size_t npage = num * size;
		npage >>= PAGE_SHIFT;
		if (npage == 0)
			npage = 1;
		return npage;
	}
	/*size_t _index(size_t bytes, size_t alignNum)
	{
		if (bytes % alignNum == 0)
		{
			return bytes / alignNum-1;
		}
		else
		{
			return bytes / alignNum;
		}
	}*/
	static inline size_t _Index(size_t bytes, size_t align_shift)
	{
		return ((bytes + (1 << align_shift) - 1) >> align_shift) - 1;
	}
	static inline size_t Index(size_t bytes)
	{
		assert(bytes <= MAX_BYTES);
		static int group_array[4] = { 16,56,56,56 };//各个分区的链接数；
		if (bytes <= 128)
		{
			return _Index(bytes, 3);
		}
		else if (bytes <= 1024) {
			return _Index(bytes - 128, 4) + group_array[0];
		}
		else if (bytes <= 8*1024) {
			return _Index(bytes - 1024, 7) + group_array[1] + group_array[0];
		}
		else if (bytes <= 64 * 1024) {
			return _Index(bytes - 8 * 1024, 10) + group_array[2] +
				group_array[1] + group_array[0];
		}
		else if (bytes <= 256 * 1024) {
			return _Index(bytes - 64 * 1024, 13) + group_array[3] +
				group_array[2] + group_array[1] + group_array[0];
		}
		else {
			assert(false);
		}
		return -1;
	}
};
//管理多个连续页大块内存跨度结构
struct Span
{
	PAGE_ID _pageId=0;//大块内存起始页的页号
	size_t _n=0;//页的数量

	Span* _next=nullptr;//双向链表的结构
	Span* _prev=nullptr;

	size_t _objSize = 0;//切好的小对象的大小

	size_t _useCount=0;//切成小块内存，被分配给thread cache的计数
	void* _freeList=nullptr;//切好的小块内存的自由链表

	bool _isUse=false;   //是否在被使用
};

//带头双向循环链表
class SpanList
{
public:
	SpanList()
	{
		_head = new Span;
		_head->_next = _head;
		_head->_prev = _head;
	}

	Span* Begin()
	{
		return _head->_next;
	}
	Span* End()
	{
		return _head;
	}

	bool Empty()
	{
		return _head->_next == _head;
	}

	void PushFront(Span* span)
	{
		Insert(Begin(), span);
	}

	Span* PopFront()
	{
		Span* front = _head->_next;
		Erase(front);
		return front;
	}

	void Insert(Span* pos, Span* newSpan)
	{
		assert(pos);
		assert(newSpan);
		Span* prev = pos->_prev;
		prev->_next = newSpan;
		newSpan->_prev = prev;
		newSpan->_next = pos;
		pos->_prev = newSpan;
	}
	void Erase(Span* pos)
	{
		assert(pos);
		assert(pos != _head);
		//1.条件断点
		//2.查看栈帧
		/*if (pos == _head)
		{
			int x = 0;
		}*/
		Span* prev = pos->_prev;
		Span* next = pos->_next;
		prev->_next = next;
		next->_prev = prev;
	}
private:
	Span* _head;
public:
	std::mutex _mtx;//桶锁
};